The present invention relates to a camera having a mechanism for changing a size of a photographing frame.
Conventionally, there has been known a mechanism for switching a size of a photographing frame. Examples of such a mechanism for changing the photographing frame size of a 35 mm format film are: one for switching between a standard size and a half size; one for switching the standard size and a panorama size; and a classic size and a hi-vision size.
Recently, needs of users to shoot photographs at various sizes have arisen. However, if the conventional frame size changing mechanism is modified to achieve a mechanism for switching the frame size among three or more sizes, the mechanism may be complicated, and the size of such a mechanism may be relatively large.
It is therefore an object of the present invention to provide an improved camera having a mechanism for switching a size of a photographing frame from among various sizes with a relatively simple structure.
For the above object, according to the present invention, there is provided a frame size changing device for a camera to change a frame size by masking part of an aperture defining the maximum size of the frame. The frame size changing device is provided with a pair of light-shielding curtain members, the pair of light-shielding curtain members being flexible, a pair of drawing mechanisms located outside of the aperture, the pair of drawing mechanism being biased to draw the pair of curtain members to move away from the aperture, respectively, a manually operable member that is manually operated to move within a predetermined movable range, the pair of curtain members to be inserted in and retracted from the aperture in accordance with the movement of the operable member, and a holding mechanism that holds the manually operable member at a desired position within the movable range.
With this configuration, since the frame size is defined by the curtain members which can be located at a desired position, various sizes of frame can be formed with a simple structure.
Optionally, the pair of drawing mechanism may include chambers and a pair of rotatable shafts housed in the chambers, respectively, the pair of curtain members being wound on the rotatable shafts, respectively, the rotatable shaft being biased to rotate in a direction where the pair of curtains being drawn in the pair of chambers, respectively.
It is preferable that the pair of curtain members move symmetrically with respect to a center line of the aperture. With this movement, the center of the frame always coincides with the center of the aperture regardless of the frame size defined by the curtain members.
In a particular case, the manually operable member is connected to an end of one of the pair of curtain members, an end of the other one of the pair of curtain members is connected with the end of one of the pair of curtain members through an interlocking mechanism.
In the above case, the manually operable member may include an operation knob and a connection shaft that connects the operation knob and the end of the one of the pair of curtain members, the connection shaft is slidably fitted in and guided by a guide slit formed on a body of the camera.
Optionally, the interlocking mechanism may include a belt, one end of the belt being secured to the end of one of the pair of curtain members, the belt being turned round a shaft member that is fixed to the camera, the other end the belt being connected to the end of the other one of the pair of curtain members, the pair of curtain members moving in opposite directions with respect to the center line of the aperture.
Further optionally, the holding mechanism may include a click mechanism defining a plurality of click points, the click mechanism preventing the operation knob from moving due to the force to draw the pair of curtain members generated by the pair of drawing mechanisms when the operation knob is located at one of the plurality of click points.
Still optionally, the holding mechanism is capable of holding the manually operable member at more than two different positions.
Yet optionally, the aperture may define a photographing frame of the camera.
In a particular case, the camera uses a Brownie film, the maximum size of the aperture corresponds to a photographing frame size of 60xc3x9790 mm, and the holding mechanism is capable of holding the manually operable member at positions that correspond the photographing frame size of 60xc3x9790 mm, and at least one of 60xc3x9780 mm, 60xc3x9770 mm, 60xc3x9760 mm and 60xc3x9745 mm.
Also in a particular case, the camera uses a Brownie film, and the holding mechanism is capable of holding the manually operable member at positions that corresponds to the photographing frame size of 60xc3x9790 mm, 60xc3x9780 mm, 60xc3x9770 mm, 60xc3x9760 mm and 60xc3x9745 mm.
According to another aspect of the invention, there is provided a frame size changing device for a camera to change a frame size by masking part of an aperture defining the maximum size of the frame. The frame size changing device is provided with a pair of light-shielding curtain members, the pair of light-shielding curtain members being flexible, the pair of curtain members being movable, within a predetermined range, to be inserted in and retracted from the aperture, a pair of drawing mechanisms located outside of the aperture, the pair of drawing mechanisms being biased to draw the pair of curtain members to move away from the aperture, respectively, and a holding mechanism that holds the pair of curtain members at a desired position within the movable range.